Apparatus and process for irradiating fluids



March 12, 1940. c. B. DALZELL 2,193,225

v APPARATUS AND PROCESS FOR IRRADIATING FLUIDS Filed lay 17, 1939 2 sheets-sheet 1 IN VEN 1 OR.

Y aha/"65 .5. flalzell March 12, 1940. c; 5 DALZELL 2,193,225

APPARATUS AND PROCESS FOR IRRADIATING Fwws Filed May 17, 1939 2 Shun-Shoat 2 IN VENTOR.

Patented Mar. 12, 1940 UNITED STATES APPARATUS AND PROCESS FOR IRRADIATING FLUIDS Charles B. Dalzell, Little Falls, N. Y., assignor to Cherry-Burro]! Corporation, Wilmington, Del.,

a corporation Application May 17, 1939, Serial No. 274,173

8 Claims.

This invention relates to improvements in an apparatus and process for irradiating substances.

The invention concerns itself particularly with the apparatus and process for irradiating fluids, such as milk, with radiant energy to thereby affect the properties of the irradiated fluid. The radiant energy most commonly used for the purpose of irradiating food substances and imparting thereto vitamin D characteristics is ultra-violet light which may be conveniently supplied by the use of an electric carbon arc lamp.

In irradiating apparatus of the type of this invention, the fluid being treated flows in a film past a source of radiant energy and the efliciency of the apparatus and process is greatly affected by the type of fluid flow secured during the irradiating process. Thegeneral arrangement of the annular metal liquid supporting shell provided with a central source of radiant energy, a distributor and a collector for liquids, as generally shown in Figures 1 and 2, is similar to the construction shown in United States Patent No. 2,139,657. Turbulent flow of the fluid being processed has been found to be a most effective type of flow. The improvement attributed to the turbulence of the liquid, especially in the treatment of opaque liquid, such as milk, is particularly due to the fact that such turbulence causes many short exposures of different particles of the fluid to the source of radiant energy.

After these many'short exposures the various particles of fluid are again mixed by the turbulent flow with the remaining particles of the fluid. The process of exposure to the radiant energy followed by subsequent mixing and re-expo'sure, not only assures the-exposure of all of the par ticles of the liquid to the irradiating energy or medium, but it has also been found that it results in the securing of a higher anti-rachitic potency due to the thorough intermingling of the irradiated and non-irradiated particles of the fluid. In the present invention a novel irradiating apparatus has been provided in which the improved process may be more effectively carried out.

The principal object of the present invention is to provide a new and novel sanitary irradiator in which the non-perforaneous or imperforatesurface over which the fluid' passes during the irradiating process has been embossed so as to improve the turbulence without producing splashing of the fluid as ityflows over the surface. Such improved turbulence is secured by obstructcausing a dispersion, distribution, intermixing and development of difference in speed and thickness of flow by the different particles of the liquid as they pass over the non-perforaneous or im perforate irradiating surface. Such a condition of turbulence in the flowing fluid results in a desired blending and uniform irradiation of the fluid to cause the frequent interchange of the liquid particles comprising the exposed layer with the liquid particles in the unexposed strata of the liquid.

With the foregoing and other objects and important features in View, the invention consists of certain novel features of construction as will be readily apparent upon the examination of the details of construction and arrangement and various combinations, as disclosed in the figures and descriptions, and also the improvements in the irradiating process involving the frequent intermittent exposure of more particles of the liquid being processed resulting from the increased turbulence of flow of the fluid being processed. All of these characteristics will be more fully described and specifically pointed out in the appended claims, reference being made to, the accompanying drawings in which:

Figure 1 is a vertical sectional view taken through the central axis of one embodiment of the invention.

Figure, 2 is a similar View showing a modified construction of the apparatus shown in Figure 1.

Figure 3 is an elevational view of a portion of the fluid irradiating surface showing the novel surface of the interior of the irradiating shelf and schematically illustrating the dispersion, l

intermingling and distribution of the fluid as it travels over the unique surface.

Figure 4 is a sectional view of a portion of the fluid irradiating surface taken along line ii-4 of Figure 3 and showing the novel surface in cross section and schematically illustrating the turbulent intermingling flow produced within the layer of fluid flowing over the novel surface.

Referring to the illustrations of the various embodiments of the invention in which like numerals identify like parts, and directing attention particularly to Figure 1, in which H3 designates a frame to which is fixed a cylindrical, imperforate sheet metal casing l I over which the fluid to be irradiated flows, an inwardly and upwardly turned flange I2 is provided at the lower extremity of the casing ll forming a collecting trough l 3 to catch the treatedliquid after passing ,overthe surface of casing H and conducting the liquid into discharge conduits I4.

The casing H is provided with a cover plate l5 3 which supports a centrally positioned bracket Hi to which is fixed an arc lamp ll depending therefrom through the approximate center of the casing I I. A fluid distributing plate I8 fixed to the lower side of the cover is adapted to equally distribute the fluid suppled by supply pipe 59 over the inner surface of the upper portion of the casing H. The entire inner surface of the casing ii consists of circumferentially staggered rows of generally extending protuberances 20 which will be more particularly referred to later. However, the arrangement of the protuberances in circumferentially staggered rows is not essential as other arrangements of the protuberances will also accomplish the function.

In Figure 2 is shown a series of circumferential baffles 22! fixed to the inner surface of the non-perforaneous or'imperforate casing l I, which baiiles tend to cause a further turbulence in the fluid being treated as it passes down over the surface of the casing. The baffles 23 also have a redistributing effect upon the fluid at periodic intervals in its passage over the surface of the casing and thereby regulate the flow of the fluid by decreasing the speed thereof. The precise nature of the cross'section of the baffles is not of ultimate importance.

The knob-like embossings, which are common to the modifications of my invention and. which improvement constitutes the apparatus element of my invention, in the preferred embodiment comprise circumferential rows 22 of protuberances Ed in uniformly spaced position about or over the entire periphery of the respective irradiating surfaces, though in the figures the protuberances have been shown only at irregular positions for the purpose of clarity in illustration. The preferred arrangement secures great turbulence. However, ununiformly, positioned knobs may also be used. The various. rows 22 of the protuberances in the preferred embodiment are so arranged with respect to an adjacent row that the vertical center line of each protuberance in one row falls intermediate the center lines of the adjacent two protuberances in an adjoining row. The size of the protuberances 28 is such as to effectively block the space intermediate two adjacent protuberances in an adjoining row, thereby to effectively divert any liquid which may flow between the two adjacent protuberances in an adjoining row. The depth, however, of the protuberances 2&3 is not sufficient to cause a rupture of, the liquid layer as it flows over the irradiating surface.

In the prior types of irradiating surfaces the fluid flowing thereover generally took the form of a laminar fllrn like flow in which the outer particles of the liquid film may travel faster than the innermost particles of the liquid film and proceed in such travel without any appreciable intermingling of the various particles of t e liquid. One of the chief advantages of the novel fluid supporting surface embodied in this invention results in the tubulent flow of the liquid as it passes over the surface engaging the rows 22 of staggered prot'uberances The engagement of the various particles of fluid with the various protuberances produces a deflection, division and intermingling of various particles of liquid as they engage the protuberances and are deflected from one side to the other and pass from. a thin film flowing over the top of the protuberances to a deeper stratum flowing intermediate the protuberances, thereby continuously interchanging the particles constituting the surface layer of the liquid with particles below the exposed surface of the liquid to secure thereby a frequent intermittent exposure of many particles of the liquid.

Such deflection, separation, rejoining and intermittent exposure of the individual liquid particles produces very active turbulence Within the liquid layer itself as it passes over the fluid supporting surface, thereby presenting each particle of fluid to the effect of the radiant energy a multitude of times as the liquid flows through the apparatus. Due to the fact that the various adjacent rows 22 of protuberances 28 are in staggered relation obviating any direct unobstructed passage for flow of fluid, the various particles of fluid which unite and pass between two adjacent prctuberances in one row will be obstructed in their flow by the engagement with a protuberance in the adjacent row. The engagement with the latter mentioned protuberance will cause a deflection in the path of flow of the liquid, part of the fluid dividing and passing about the protuberance on one side, part on the other side and a small portion passing in a thinner film over the top of the protuberance. After passing over the protuberance the same particles of fluid will not be united on the opposite side. Some of the liquid which was diverted to one or the other side of the protuberance will have joined particles of liquid similarly diverted around an adjacent protuberance. The process of rejoining and redivision produces a very desirable condition of tubulence and distribution of the fluid as it passes over the fluid supporting surface, thereby assuring the frequent exposure of substantially all particles of the liquid to the source of radiant energy.

In Figures 3 and 4 an attempt has been made to illustrate the nature of the flow of the fluid over the knob-like embossings. In Figure 4 the effect of crowding of the various particles of liquid into a channel intermediate two adjacent protuberances and the subsequent redivision of the same particles in a different proportion and.

their still further subsequent reuniting is illustrated by the use of dotted lines and full line arrows.

From experimental tests it has been found that, while a film of liquid in flowing over a flat sheet or a sheet with parallel corrugations transverse to the direction of flow of the liquid will not cause a dispersion of a stream of colored fluid introduced into the film, a surface provided with knob-like protuberances, such as illustrated in Figure 3, will cause a great dispersion of such a stream of colored fluid as the film of fluid passes over the knob-studded surface. This dispersion progresses somewhat of the order as illustrated in Figure 3.

The attainment of such a condition of dispersion would in itself have a substantial beneficial effect in a device of the type constituting the subject matter of this invention, as well as a substantial improvement in the process. However, this improvement is still further increased by securing a dispersion or distribution, intermingling or mixing in a third dimension whereby great turbulence is produced, as illustrated in Figure 4. As shown in Figure l, the thickness of the film of liquid, in passing over the crest 23 of the protuberance 26, is comparatively thin with respect to the depth of the layer of liquid as it contacts the protuberance after passing intermediate two adjacent protuberances in an adjoining row, as shown by 24 in Figure 4.

plishment of such a degree of turbulence, distribution, dispersion, intermingling, andchange of exposed surface as to greatly improve the irradiating efliciency of the radiant energy supplied to or impinged against the surface of the flowing fluid.

Although I have shown and described certain specific embodiments of my invention, many possible modifications thereof can be made. The invention, therefore, is not to be restricted except insofar as'necessary by the prior art and the spirit of the applied claims.

The invention is hereby claimed as follows:

1. In a device of the class described, a nonperforaneous supporting surface for aflowing fluid to be irradiated over one side thereof, a source of radiant energy adapted to impinge anirradiating medium against the surface of the fluid. flowing over said supporting surface, and a series of circumferential rows of protuberances on said supporting surface, said protuberances in each row being staggered with respect to the protuberances in the adjoining row.

2. The process of irradiating fluid which comprises causing the fluid to flow in a thin sheet of ununiform thickness over an imperforate liquid supporting surface having liquid flow obstructions in the form of protuberances, subjecting the particles of said fluid to an irradiating medium while flowingin a thin sheet of ununiform thickness with different particles flowing at different speeds, continuously obstructing the sheet-like flow of the fluid, and causing the individual particles of the fluid to flowin circuitous paths about said protuberances whereby the individual particles of fluid will be intermingled one with another, causing three-dimensional turbulence within said fluid substantially throughout its entire passage over said supporting surface and producing a continuous change of particles constituting the exposed layer of the liquid.

3. An irradiating device for fluids suchas milk which are relatively opaque to radiant energy waves to be used in the irradiation of fluid, comprising. a source of radiant energy, and an imperforate fluid supporting surface encompassing said source of radiant energy and having spaced flow passages for fluids on one side thereof, said passages comprising substantially verticaland inclined segments alternately arranged with the substantially vertical sections being laterally staggered with respect to one another and bounded by protuberances on said fluid supporting surface.

4. An irradiating device for relatively opaque fluids comprising, in combination, a source of radiant energy, a non-perforaneous fluid supporting surface encompassing said source of radiant energy, and a multiplicity of fluid diverting protuberances constructed and arranged to alternately restrict and enlarge the multiplicity of passages for fluid flow over said surfaceintermediate said protuberances, said diverting protuben ances being out of vertical alinement with adjacent protuberances, whereby the several portions of the relatively opaque fluid will be repeatedly mixed, blended and exposed to the source of radiant energy as it flows over the liquid supporting surface and intermediate said protuberances on said non--perforaneous flow supporting surface.

5. An irradiating apparatus comprising a liquid supporting surface exposed to the action of radiant energy, means for passing liquid to be irradiated onto said liquid supporting surface, and knob-like projections on said surface for obstructing the uniform laminar flow of the liquid andcausing a turbulent flow of said liquid as it passes over said surface under the influence of said radiant energy, said protuberances being so positioned on said supporting surface as to cause the liquid to intermittently flow in films of radically varying thickness and transverse dimensions, marked by the turbulent action of liquid particles within the liquid as it passes over the supporting surface.

6. An irradiating device for irradiating a relatively opaque liquid such as milk with ultra-violet rays to produce therein a vitamin D effect with out otherwise substantially affecting the liquid ccrnprising, in combination, a liquid supporting shell exposedto the action of a source of radiant energy, a liquid distributor for applying liquid to be flowed over the interior surface of said shell in a layer thicker than that through which said rays will effectively penetrate, and a multiplicity of protuberances on said surface for disturbing the uniform flow; of the liquid over said surface, whereby the individual particles of liquid will be repeatedly exposed to the effect of said rays and then remixed with the remainder of the liquid in unexposed positions. 1

"7. The method of irradiating a liquid by exposing a layer thereof to the effect of ultra-violet rays to produce a vitamin Deifect therein which comprises the steps of flowing the liquid in a layer over an imperforate liquid supporting" surface while subjected to the irradiating energy of ultra-violet rays, continuously and concurrently increasing the flow of some of the individual particles of liquid While retarding the flow of other individual particles of liquid and intermittently alternating said step with respect to the individual particles of the liquid by obstructing the free flow of some of the individual particles of liquid by protuberances on said imperforate supporting surface to cause some portions to flow in thinner layers than others, and concurrently therewith causing turbulence within the entire layer of liquid flowing over and around said protuberances by intermingling the fast flowing individual particles of liquid with the slower moving individual particles of liquid, whereby a frequentinterchange of particles of liquid constituting the layer exposed to said rays is secured.

8. A device of the class described comprising, in combination, an imperforate fluid supporting surface forsupporting fluid to be irradiated, a

source of radiant energy adapted to impinge an irradiating medium against the surface of a layer of fluid flowing over said surface, and a multitude of protuberances on the surface of said supporting surface to substantially obstruct the flow of liquid over said surface and to cause a degree of turbulence of the particles of the liquid within said layer of liquid to assure a frequent change of particles constituting the surface exposed to said radiant energy.

CHARLES B. DALZELL. 

